Monthly Archives: September 2015

Roman sandals

Where do shoes come from?

boot
A Boot

The earliest reference to shoes are some kind of findings from about ten thousand years ago. People are, since time immemorial times, learned that the soles of the feet are sometimes good to be protected against the cold, sharp stones or other harmful effects. On the other hand, where circumstances permit, also being bare footed has always been in fashion.

Prior to year 1000 numbers of different types of sandals were used, among other things, the Greeks, for whom the use of the shoes had been a wealth and status symbol. Roman sandals, in turn, developed into simple boots. Celts at 1100’s used leather shoes, which were heated by the fur inside of them.

medieval shoe
A medieval shoe

In the Middle Ages shoes could be up to half a meter long with tapered tips. In the 1500’s came into fashion unwalkable, up to half a meter high platform soles, Chopin. In 1600’s it became more common to use shoe laces to tighten the shoes. The French Sun King Louis XIV used platform shoes and made courts wild around Europe.

Little Green Boy in platform shoes
Little Green Boy in platform shoes

Previously shoes were always handmade. Shoemakers guild was appreciated and they sewed shoes together from leather pieces. Today, cobblers, mainly fix shoes and copy keys. 1700’s the shoe industry developed and mass production began. The first shoe factories were founded, and as well the first shoe store opened in Boston. When 1900s’ approached , sports shoes were invented, among other things and manufacturing of shoes became easier thanks to the invention of the sewing machine. 

Today, most shoes are manufactured in factories in large Asian countries. Shoes might be made partly by hand, but now the factory can produces thousands of pairs of shoes a day, while the shoes entirely made by hand by the shoemaker could take a week.

Stars forming

Where do stars come from?

Little Green Boy and Stars
Little Green Boy and Stars

As stated earlier in the stars and space articles, the space according to present knowledge emerged from the Big Bang with stars and planets and everything. The sun is the closest star to us – that’s why it looks so huge. Other stars are sometimes thousands of times larger than the sun, but they are so far away that they look like small dots in the night sky.

The stars will go out, and new ones are constantly born. Because the stars are so far away, their light’s trip here takes millions of years. Thus, how we see the starry sky is really like an old photo of what the stars looked like millions or billions of years ago. It may be that some of the stars we see are actually already gone and new ones have emerged to replace them.

How, then new stars  are born? The stars are created when the cold gas clouds are condensed together under their own weight. In the end, the resulting star settles to a stable state. At this stage the star receives energy from nuclear reactions, the fusion of hydrogen. Our sun is at this stage. Our Sun is about five billion years old and it is in the middle of its life cycle.

When all of the hydrogen starts being used, moves the star to fuse helium (the same substance that is in gas balloons) and the star’s core shrinks and heats up, but the outer parts expand and cool down. Thus the star becomes a red giant. After this, the stars with the mass of our sun become planetary nebula, with a central star being a dense white dwarf. By the time the fog will disappear, and cool white dwarf remains.

Heavy stars, about 10 times the mass of our Sun, are destined into a supernova explosion, which results in a gas cloud, in addition to either a neutron star or a black hole. Supernova is a huge explosion, where the fading star burst like a bomb and throws material all around the space. A black hole is a body, which traction force is so strong, that it will suck up everything – even light. It is believed that in the middle of our Galaxy is a huge black hole, whose name is Sagittarius A.

Moon

Where does the moon come from?

Little Green Boy and Moon
Little Green Boy and Moon

The Moon is Earth’s only natural companion, a satellite. Moon rotates around Earth, but there are also a lot of small man-made objects, such as weather and communication satellites and old spacecraft parts – space debris. The moon has circled the earth billions of years, but not always. When people were up there in the 70s, they brought back rock samples, that have launched a theory that another planet collided with the young Earth, and the remaining pieces formed the moon. However, this theory is not the only one.

Astronaut on moon
Astronaut on moon

The moon reflects the sun light, and is the second brightest object in the sky after the Sun. The moon appears to be yellow, but it is actually gray and cold stone ball. Moon in the night sky has always been a fascinating destination for people. The different phases of the moon, full moon, crescent etc. depend on how the Earth’s shadow covers the moon at different times of the month. Month is the time it takes moon to circumvent the Earth.


Many other solar system planets have moons – usually more than one. Moons of other planets have different names, such as the Martian moons Phobos and Deimos. Earth’s moon, however, has no other name. Moon strongly influences life on Earth. Eg. Ocean tides are due to lunar gravity.

 

Lunar Rover
Lunar Rover

In the old days people imagined seeing oceans and cities on moon. It was believed that the moon is home to the moon people. Really the moon is a pretty empty place. There are only a few rocks, spacecraft parts and some equipment, like Lunar Roving Vehicles used by the astronauts. Cars could not be taken back, so they were left on the moon forever. In addition there are few American flags and golf balls that the astronauts struck while visiting .

Hedgehog

Can a hedgehog eat a snake?

Snake and hedgehog
Snake and hedgehog

The hedgehog is a small, spiny insect nocturnal insect-eater. The hedgehog as a species, is very old. Hedgehogs have roamed the earth almost unchanged for millions of years. Hedgehogs, may have been existing already at the time of the dinosaurs.

When grandma and grandpa went to school, old school books had a picture, which presented a hedgehog being the main enemy of the viper. The hedgehog , however, would not invade living adult snake snake. They might anyway eat the carcasses of dead snakes.


Hedgehogs natural food are beetles, Shield Bugs, millipedes, ants, earwigs and spiders. However, hedgehogs also eat caterpillars, snails, earthworms, frogs, lizards and mice. 

For your garden hedgehog you can provide, for example, boiled fish and crushed peanuts. The fish has to be cooked so that the hidden parasites die and do not spread in the body of the hedgehog. You can also provide, say, cat food, both dry and wet food, because they do not contain very large quantities of salt or strong seasonings, which can be detrimental to hedgehog. Hedgehog insectivore teeth are not suitable for milling, so hard pellets are recommended to be soaked in water before offered.

MRI Scanner

What is Magnetic resonance imaging?

Little Green Boy in magnetic scanner
Little Green Boy in magnetic scanner

Magnetic resonance imaging is a technique that allows doctors to see inside the human being. In humans, there is no bonnet, which can be easily opened, such as in a car. It would be inconvenient if you always should do the surgery in order to get to investigate what is happening inside the human.

To view inside a person, there are number of different methods. The old method is the X-ray imaging, which enables you to easily see, for example, the skeleton. In this way, it is easy to study, say, whether the leg has a fracture. Other older methods are eg. Endoscopy, in which a small camera is inserted into the man in, for example, orally.

MRI_brain
MRI image of brain

Magnetic resonance imaging (MRI) is one of the latest methods. A large electromagnet and a computer form a kind of camera that can take a photo of a person in slices. Magnetic picture looks a little sliced ​​potato and cone an easily see how the different layers within the human look. MRI can be used to investigate, for example, the most important part of the human body, the brain and their functions.

Jurta

Why do houses exist?

Little Green Boy in Treehouse
Little Green Boy in Treehouse

The house appears obvious, but all do not live in houses. Around the world, people live in a variety of ways. Recently, the paper told of a girl who lives in a train and a woman who has been living in the airport. In Thailand there are families who live in abandoned airplanes. In Mongolia it is usual to live on a thick felt-made tent, jurt. Certain tribes live in mud huts and some live permanently in a tent or caravan.

However houses have their pros and cons. Houses are easy to heat, and they provide good protection from wind, rain, wild animals and uninvited guests. On the other hand the houses are expensive and require a lot of care. Houses can not be moved. That is one reason why, for example, the circus people living in caravans.

Telephone

Why telephones do exist?

Little Green Boy on phone
Little Green Boy on phone

How did you contact other people before the invention of telephone? Signal drums, smoke signals, postal wagons, couriers, telegraph? More than one persons have been considered to be the inventor of the phone. One of the best known (though perhaps not the very first) is Alexander Graham Bell. He is said to have spoken on the phone the first words: “Watson, come here, I need to talk.”

In your mother’s and father’s childhood  so-called, landline telephones were the only form of phones and mobile phones and video calls would never even been dreamed of. They could be seen only in science fiction movies. Radio phones were used by authorities and the truck drivers. In general, every home had one telephone and it was a phone in the hallway on the table. On the table, then there was a small notepad, which was used to draw doodles while the phone’s twisted cord was wrapped around your finger to pass the time during a long phone call. Normally, the phone did not show who is calling, so we always had to answer objectively with your own name or a phone number.

Today, the phone is taken for granted. People are reachable everywhere and always. The phone is a convenient way to keep in touch with relatives who live further away. Smoke signals, jungle drum and shouting would not carry very far.

What are stars?

Stars
Stars

The sun is actually a star. It appears much larger, because it is so much closer. You can try out at home by putting your thumb in front of your eyes, and comparing it to the more distant standing  mum. Mother appears the size of a thumb, because she t is further away. This phenomenon is called a perspective.

The stars are huge fireballs. Actually, they have a huge amount of gas, whose own weight to keep star together. The star is an ongoing fusion reaction, a bit like nuclear power plants. The result is an enormous amount of light, warmth and a lot of different types of invisible radiation.

After Sun the closest star is Proxima Centauri, which is about four light-years away. It is so far away that with the world’s fastest spaceship it would take more than 73 000 years to get there. It is a long time. 73 000 years ago, the cave men learned to use tools and make drawings in the cave walls. The same spacecraft would circulate around the earth in about three quarters of hour.

There is almost infinite number of stars in space. Most of them are so far away that they can not be seen with the naked eye in the night sky. There are much more stars, than there are grains of sand on the beach. Around each star may have planets such as Earth.

Stars form star clusters and galaxies. Galaxy may be hundreds of billions of stars. Galaxies tend to look helical wafer. Our galaxy, the Milky Way, may be visible in the night sky as a light stripe. The Milky Way is a spiral galaxy, but we see it from the inside so it appears as a stripe.

Why there are clouds?

Plane over clouds
Plane over clouds

Clouds are made of water. In general, they consist of water droplets or ice crystals. As the droplets and crystals grow sufficiently heavy, they fall down as rain. Fog is a cloud that reaches the earth’s surface. The clouds are created when moist air rises it cools and condenses into very small droplets or ice crystals.

Clouds cool the planet by reflecting solar radiation back into space. On the other hand they have a warming effect in the winter also prevents the heat escaping from the Earth’s surface.

In addition to the regulation of the temperature, the clouds are vital for plants and animals, as they carry water from the rivers and the wetter regions to drier regions. If there were no clouds, it would not rain water and many plants die from drought. Then there would be no food for the animals.

In deserted lands it is usually not raining. They are dead spots, in which only species that can survive are those, that specialize in surviving such hostile environments.

Where do dogs come from?

Wolf
A wolf

“Where does man come from-article talked about Charles Darwin and evolutionary theory.  When animals get babies, they are all different. Then, when these babies grow to adulthood and have their own offspring, some of their properties inherited by their descendants.

Animal breeding means that you look for certain properties in animals, and pick those to reproduce. When you keep doing this over decades, all of that species share the same properties. Take always hens that lay largest eggs and little by little, all the eggs of all hens will be larger.

The dog has been bred from wolf. People have domesticated wolves as their pets and most well behaving ones made puppies together and this went on over and over again. This way the current dog breeds were born.